Thanks for playing! Glad you enjoyed it. Ending 5 is one of the more difficult endings to reach.
For the computer voice, I recorded my own voice and used Audacity with the Krush VST plugin https://www.tritik.com/product/krush/. Then I just tweaked the settings until it sounded good. It helps that my voice is already kind of monotone sounding ;)
And yeah, my voice is saying 0 8 3 5. Sounds like you figured out where to use those numbers :)